An operations semantics for pure dataflow

We prove the equivalence between an operational and an extensional semantics for pure dataflow. The term pure dataflow refers to dataflow nets in which the nodes are functional (i.e. the output history is a function of the input history only) and the arcs are unbounded fifo queues. Gilles Kahn gave a method for the representation of a pure dataflow net as a set of equations; one equation for each arc in the net. We present a complete proof that the operational behaviour of a pure dataflow net is exactly described by the least fixed point solution to its associated set of equations. Our model is completely general since our nodes have the universality property, in that, for any continuous history function there exists a node that will compute it. Moreover since our nets are not built from a set of sequential primitive nodes the model is not in the communicating sequential processes framework. On the contrary our nets have the abstraction property in that any net can be collapsed into a node. The above proof gives complementary ways of viewing pure dataflow nets, that is, as either sets of equations or as graphs. It moreover gives rise to an elegant equational dataflow language. Pure dataflow then takes on an important role since it is a correct implementation for such a functional programming language; nodes being implementation of continuous history functions; arcs and datons being implementations of histories; and nets being mechanisms for computing the solutions to sets of equations

Fluid Simulations of the Plasma in the Negative Ion Source - SPIDER

openIl reattore a fusione nucleare ITER sarà riscaldato da fasci di neutri veloci generati dall'accelerazione e neutralizzazione di ioni negativi, prodotti in un plasma accoppiato induttivamente in RF e che si espande in una regione contenente un filtro magnetico. In questa tesi è presentato un modello fluido bidimensionale autoconsistente della sorgente, basato su equazioni di continuità separate per le differenti specie di particelle, l'equazione di Poisson per il potenziale di plasma e l'equazione di bilancio energetico degli elettroni per la temperatura elettronica. Inoltre, i flussi di particelle sono calcolati assumendo l'approssimazione "drift-diffusion". Il metodo numerico, basato su uno schema semi-implicito, utilizza l'approssimazione di volume finito e adotta una discretizzazione a 9 punti in modo da prendere in considerazione l'anisotropia dovuta al campo magnetico. In più, il metodo numerico è implementato da un codice in FORTRAN 95 (FSFS2D) che è stato testato in fase di sviluppo l'anno scorso in una geometria semplificata rettangolare. Le simulazioni attuali tengono conto di una geometria più accurata e realistica rispetto ai reali driver di SPIDER. È investigata l'influenza del potenziale di bias, del campo magnetico, della pressione del gas neutro e della potenza a radio-frequenza sulle proprietà del plasma e si instaura un confronto con i precedenti risultati in geometria semplificata. Si mostra come la geometria più corretta di SPIDER fornisca risultati in generale accordo con quelli ottenuti nel caso rettangolare con, tuttavia, significative differenze nella regione del driver.The ITER fusion reactor will be heated by fast neutral beams generated by accelerating and neutralizing negative ions, produced in a RF inductively-coupled plasma and expanding through a region featuring a magnetic filter. In this thesis a self-consistent two-dimensional fluid model of the source is presented based on separate continuity equations for the different particle species, Poisson equation for the plasma potential and the electron energy balance equation for the electron temperature. In addition, the particle fluxes are calculated assuming the drift-diffusion approximation. The numerical method, based on a semi-implicit scheme, makes use of the finite volume approximation and the 9-points-discretization is exploited in order to take into account the anisotropy due to the magnetic field. Furthermore, the numerical method is implemented in a FORTRAN 95 code (FSFS2D) which was tested in the development phase on a simplified rectangular geometry during the last year. The present simulations take into consideration a more realistic and accurate geometry with respect to the real driver volumes in SPIDER. Influence of the bias potential, magnetic field, neutral gas pressure and radio-frequency power on the plasma properties is investigated and compared with the previous results in simplified geometry. It is shown that for the more correct SPIDER geometry results are generally in agreement with the ones obtained from the rectangular case with however significant differences in the driver region

Language and Art Are One: Art, Life, and Politics as Action in Space

On May 1, 2014, the UNM Department of Spanish & Portuguese and the LAII co-sponsored a presentation with author, artist, and community activist Marcus Vinícius Faustini. Faustini discusses his work with youth in Rio de Janeiro\u27s favelas, where he collaborates with them to develop socio-cultural initiatives that will positively impact his society.https://digitalrepository.unm.edu/laii_events/1069/thumbnail.jp

Selective Laser Sintering of Passive Dynamic Ankle-Foot Orthoses

Passive dynamic ankle-foot orthoses (AFO’s) are used to improve gait performance in those with various neuromuscular disorders. An important design characteristic of passive dynamic AFOs is the storage and release of elastic energy within its structure to help satisfy the energetic demands of walking. Thus, minimizing energy dissipation through internal friction is a fundamental criterion for selecting the appropriate AFO material. This study compared the mechanical damping of a carbon-fiber AFO to three geometrically identical AFO’s fabricated using selective laser sintering with different materials. Mechanical damping characteristics ranked the materials as Nylon 11 (best), followed by DuraformTM PA and DuraformTM GF (worst).Mechanical Engineerin

CETICISMO E PRINCÍPIOS EPISTÊMICOS

A identificação e análise de princípios epistêmicos têm possibilitado ganhos significativos no estudo do ceticismo nas últimas décadas, isso não significa que estejamos próximos de um consenso sobre quais princípios devem ser aceitos. Entendendo p como qualquer proposição que geralmente admitiríamos saber, como “aqui há uma mão”, e sk como alguma proposição incompatível, como “estou sendo enganado por um gênio que me induz a crer em coisas que não existem”, o argumento canônico para o ceticismo acadêmico pode assim ser formalizado: (1) Se S está justificado ao crer que p, então S está justificado ao crer que ~sk; (2) S não está justificado ao crer que ~sk, logo, (3) S não está justificado ao crer que p. Implicitamente, pode-se notar: o cético advoga que a relação epistêmica tida com uma proposição deve ser preservada nas proposições decorrentes dessa e, uma vez falho o cumprimento dessa exigência, resulta-se inescapavelmente no ceticismo. Para resolver essa questão, alguns filósofos rejeitaram o ceticismo negando a premissa (1). Outros, como Klein, concedem (1) ao cético, porém negam sua conclusão, apontando que este falha em sua defesa de (2). Discute-se aqui a viabilidade dessas alternativas

Barium alginate capsules for 3D immobilisation of living cells: morphology, membrane properties and permeability

Encapsulation in a barium alginate membrane is a promising strategy to obtain a three dimensional culture of living cells: membrane properties are crucial for a realistic clinical application. A one-step encapsulation technique, recently developed for controlled release of boar semen, was employed to prepare barium alginate and protamine-alginate membranes: permeability to two model molecules (haemoglobin and glucose) was evaluated. Capsules were evaluated for technological properties and scanning electron microscopy was used to examine the external morphology of the capsules and the 3D distribution of the cells within the core. The results indicate that 3D arrangement and cell shape are maintained, capsule dimensions and mechanical properties can be modulated, as well as their permeability to model molecules such as haemoglobin and glucose

Apgar score or birthweight in Chihuahua dogs born by elective Caesarean section : which is the best predictor of the survival at 24 h after birth?

In the dog, the correct management of parturition and the prompt neonatal evaluation and assistance can reduce the perinatal mortality rates that are particularly high in toy breeds. Newborn evaluation and factors addressing prognosis are pivotal to guarantee the correct neonatal assistance. Assessment of the Apgar score with viability classification and birthweight are recognized as predictors for neonatal survival in dogs, but breed-specific data are needed for a more feasible application in the dog species, in which wide differences among breeds are known. The present study aimed therefore to: (a) assess the role of Apgar score and birthweight as predictors for the survival of Chihuahua newborn puppies in the first 24 h of life; (b) to assess a cut-off of the Apgar score and birthweight values that can predict the survival of Chihuahua newborn puppies in the first 24 h after birth; (c) to assess the possible effect played by maternal parity, newborn gender and litter-size on Apgar score in Chihuahua newborn puppies, in order to provide breed-specific data for a better neonatal assistance..Data obtained from 176 normal developed Chihuahua puppies born by elective Caesarean section, showed that 62%, 28% and 10% of puppies were classified in the Apgar score classes 7\u201310, 4\u20136 and 0\u20133, respectively, with survival at 24 h after birth of 97%, 96%, 39%, in the three Apgar classes of viability, respectively. Apgar score was a better predictor for survival at 24 h after birth than birthweight (AUC 0.93, P < 0.0001; AUC 0.69, P < 0.01, respectively). Litter-size of 7 puppies/litter plays a negative effect on Apgar score. Apgar score is a better predictor of survival at 24 h than birthweight, and the best cut-off of Apgar score for survival at 24 h after birth is 4, with 96% sensitivity and 77% specificity. The different proportion of \u201cnormal viable\u201d and \u201cless viable\u201d neonates in comparison to other studies highlights that Chihuahua puppies born by elective Caesarean section should be carefully evaluated at birth to provide correct assistance